In a gear mechanism structured in a geared motor or the like, engagement of gears with each other is sometimes utilized as a stopper mechanism for restricting a range of a turning angle of a gear. Specifically, in a gear mechanism having a first gear and a second gear engaged with the first gear, for example, a structure has been proposed in which a valley part between tooth parts in the second gear is filled up and used as a stopper part (see, Japanese Patent Laid-Open No. 2008-261401).
According to this structure, when a tooth tip part of a tooth part of the first gear is abutted with the stopper part of the second gear, the first gear is unable to turn further more and thus turning of the first gear is stopped.
However, in the structure described in the above-mentioned Patent Literature, when turning of the first gear is stopped by the stopper part provided in the second gear, a turning force of the first gear is concentrated on the tooth tip part of the first gear and thus damage such as breaking, deformation and a crack may be easily occurred in the tooth part.